This paper describes the effect of static electricity and humidity on friction characteristics between plastic film and steel roller.We used Polyethylene terephthalate firm,which is used in many industries due to strength from an external force and stability from chemicals.As a result,friction coefficient was increased with a decrease of the film thickness and increase of the humidity.This is because that electric charge on the plastic film was increased with a decrease of the firm thickness.The amount of real contact area was increased due to electrostatic attraction,which works between the film and roller.The friction force is a resultant force of sharing force for tear up the adhesion area,real contact area.As an increase of the humidity,amount of water particles between the film and roller increased and they works as attractive force,which makes an increase of the real contact area.